I dont know your knowledge on cars so please dont take offense if my idea;s sound to obvious. Have you checked you battery connections? Did one come loose? I mean check it GOOD! I had the same thing happen to me Lunchbox (Thanks) just had to make sure the wires to the battery where connected well. Even if they look like they are well connected I would loosen them up a little and turn the terminals around the posts just a little bit. Do any of your lights come on? Do you get a clicking sound? Any DETAILED information will help diagnose the problem. I help something I said here helped if not I am sure we can get it fixed
GTi Dave